Many kinds of portable gas measuring devices are known, which must be carried by persons, who are in areas, in which they may be exposed to harmful gases. Such portable gas measuring devices must be routinely tested for their operability, i.e., whether they react at all to the test gas or test gases to be detected by them. Besides such a mere operating test, test gas with a known concentration can be fed to the gas measuring device in a calibrating station in order to adjust the test signal of the gas measuring device.
A test station of the type mentioned in the introduction is the Dräger E-Cal station. This station is a calibrating station with a modular design for the automatic adjustment and for automatic operating tests of portable gas measuring devices. The test station comprises a main unit, including a control and analysis unit (for example, a PC). Further, a plurality of test modules connected to the main unit for the purpose of exchanging data are present, into which each gas measuring device can be inserted for testing. Means are provided for detecting the type of the respective gas measuring device that has been inserted into a test module and for determining therefrom the test gas or test gases required for this device type. The main unit comprises a plurality of gas inlets for different test gases. Under the control of the control and analysis unit, each test gas is conducted from a selected gas inlet in a common gas line, to which all test modules are connected. In the prior-art station, tests are controlled centrally by the main unit. In this case, the main unit controls the test schedule, such that first the test module, into which a gas measuring device is the first to have been inserted, is processed. A plurality of gas measuring devices may also be inserted at the same time into a plurality of test modules and the tests are then started centrally at the main unit, after which all gas measuring devices that require a defined test gas are supplied with this test gas in parallel.
Test stations for gas measuring devices, into which a plurality of gas measuring devices of the same type can be inserted, which are then supplied in parallel with the same test gas or the same test gas sequence and are tested in parallel, are also known from JP 2006 003 115 A and U.S. Pat. No. 7,530,255 B2.
In everyday operation, however, the situation frequently arises that a plurality of operators insert their gas measuring device into a test module chronologically one after the other and then want to have a test result as soon as possible. In this situation, in the test station according to the state of the art, first only the first gas measuring device inserted is tested and, then one gas measuring device after the other is separately tested in the sequence of their input.
In the processing of the first test module with the first gas measuring device, at first the type of the gas measuring device that has been inserted into the test module is detected. This may take place, for example, by reading out a memory in the gas measuring device, in which the device type is stored. Which test gases are required for each device type are also stored beforehand When, for example, the test gases A, B and C are required for the currently first inserted gas measuring device, then the main unit first selects the gas inlet for the test gas A and conducts it further to the test modules by means of the common gas line, after which one proceeds with test gas B and finally with test gas C until all the tests have been carried out for the gas measuring device inserted first into the test module. Then, the main unit proceeds with the processing of that test module, into which the next gas measuring device has been inserted after the first one. In this case, a plurality of other gas measuring devices may also have already been inserted into test modules during the testing for the gas measuring device in the one test module. These gas measuring devices are then chronologically successively processed one after the other, whereby each of the test gases are fed to a gas measuring device in a test module in accordance with the test gases required for this device type. The sequence of the processing of the test modules with inserted gas measuring devices takes place according to the chronological sequence of the insertion of the gas measuring devices into the respective test modules.
The prior-art test station can still be improved for certain usage situations, because in the situation, in which an operator is faced with a gas measuring device at the test station and has inserted his gas measuring device into a test module and the testing for this gas measuring device has been started by the main unit, another operator may insert the operator's gas measuring device into another test module, but the testing for this other test module may only be started by the main unit after conclusion of the test for the first gas measuring device. In such a situation, or when still other operators want to use the test station at different times, only one gas measuring device is tested at a time. Moreover, the test gases, which are fed by means of the common gas line, are each only used for one gas measuring device in one test module in such situations.